Saturday, July 17, 2010

Sleep Apnea? Meat And Cheese May Not Be Your Friends

You go to bed, fall asleep, and wake up. You visit the loo and return to bed, fall asleep, and wake up. Another trip to the bathroom? Frequent nighttime urination is one indication of sleep apnea. It may not be the need to urinate that's waking you, but the need to breathe.

Sleep apnea, episodes of shallow or absent breathing while asleep, is not uncommon. About 1 in 5 adults have it to some degree (a minimum of 5 episodes an hour); most don't know it's occurring.1 If you are overweight, you are likely in that 20% prevalence rate. (About half of people with diabetes experience it.2)

It's serious. The decreased blood oxygen (from inadequate air flow to the lungs) tells your brain to wake you up so you can breathe better. The cycle of falling asleep, disturbed air flow, and waking up, over and over, increases levels of stress hormones that raise heart rate and blood pressure. Hypertension is an almost guaranteed fallout of sleep apnea, as are behavioral problems. Heart disease and other elements of the metabolic syndrome (insulin resistance and blood glucose abnormalities) are also linked.

One of the first studies to examine the diets of people with sleep disordered breathing (SDB), including sleep apnea found:3

"The results indicated that even after adjusting for BMI, age, and daytime sleepiness, subjects with very severe and extremely severe SDB (RDI ≥ 50*) consumed a diet that was higher in cholesterol, protein, total fat, and total saturated fatty acids. These findings were most evident among women."

*RDI is Respiratory Disturbance Index. Individuals with an RDI ≥ 10 events/hour were considered to have obstructive sleep apnea.

Although obesity is a risk factor for sleep apnea, this study found that - apart from being overweight - a high-fat, high-protein diet led to disordered nighttime breathing. Cholesterol and protein, nutrients typically found in foods of animal origin, were especially strong indicators. Trans fats, total fat, and saturated fat followed close.

It's hard to know if you have apnea without an outside judge, be it the person who bears witness to the characteristic snoring or a doc. Daytime sleepiness is a giveaway. So is a dry, scratchy throat (from snoring). Irritability, mood swings, and aggression are all related to sleep apnea. So is hunger...

The disturbed sleep increases levels of an appetite-stimulating hormone (ghrelin), and decreases levels of an appetite-suppressing hormone (leptin). It also increases the appetite-stimulating neuropeptide Y. This all leads to food cravings and more eating during the day ... which can lead to weight gain ... which can worsen the apnea.

You don't have to be overweight to have sleep apnea, but if you are, losing weight seems to lessen it. From the looks of this study, eating a lower fat, plant-based diet may also help.

The man in the photo is wearing a continuous positive airway pressure (CPAP) machine. It maintains blood oxygen levels by keeping airways open via pressure. You still have to do the breathing. If you use one, I'm curious what you think of it.

Hi Erin. What a sleuth. You're right. That first reference from 2002 has a whole section on menopause. Looks like the risk is higher after menopause and can be lessened with hormone replacement therapy. But exactly why the risk is higher is ... complex.

@Bix: Correlation does not equal causation! This study doesn't even mention carbohydrate intake, let alone micronutrients, fitness level, and a plethora of other factors which could cause sleep apnea. This study does not prove anything.

The study I referenced (http://www.aasmnet.org/jcsm/ViewAbstract.aspx?pid=27274), does assess many of these variables. Re: carbs, they weren't associated:

"We found that RDI ≥ 50 was significantly associated with consumption of greater amounts of total calories, protein, fat, total saturated fatty acids, trans-fatty acids and cholesterol, but not carbohydrates, sucrose or dietary fiber."

There was quite a bit of analysis Re: physical activity, BMI, energy expenditure, etc. How it was assessed, how it was associated. In fact, greater episodes of apnea were associated with more physical activity, which surprised me. But it was attenuated by BMI. Pretty interesting I thought.

"Assessment of physical activity was gathered from participants using the Arizona Activity Frequency Questionnaire (AAFQ). This instrument distinguishes between different types of physical activity, including recreational, household, and leisure activity. In addition to caloric expenditure, it provides the amount of activity in metabolic equivalents or the ratio of work metabolic rate to a standard resting metabolic rate (METs). One MET is roughly equivalent to the energy cost of sitting quietly or 0.0175 calories per minute per kilogram of body weight (kcal/minute/kg).20 This instrument has been validated using doubly labeled water and has been shown to be effective in predicting total energy expenditure and physical activity energy expenditure in epidemiological studies."

Re: Campbell's "The China Study," and Ben's link which challenges his findings ... Campbell responded to it here:

http://tynan.net/chinastudyresponse

One critic of Denise Minger's post (Ben referenced it), said:

"I've taken a look at Denise's analysis. I'm an epidemiologist, and on top of that my research focuses on cancer (not that this makes me completely infallible, but at least I feel equipped to provide an informed critique of her statistical capability). Dr. Campbell was certainly gracious in his response to criticism, but I cannot be so kind. Denise is incredibly naive in her crude analysis of the raw data. She uses correlations and ecologic comparisons to draw conclusions about relationships between diet and outcome (cancer, cardiovascular disease, etc.). WRONG WRONG WRONG!!"

More here:http://www.30bananasaday.com/group/debunkingthechinastudycritics/forum/topics/a-cancer-epidemiologist

I was diagnosed with sleep apnea about 2 years ago. When I was diagnosed I realized that if I had it, my husband had it even worse. Soon he was diagnosed as having severe sleep apnea. We have both been using C-Pap machines ever since. We use them at home and we travel with them as well. We both used to have trouble with falling asleep at the wheel of the car on trips of more than 1/2 hour. We no longer have those problems even driving at night. I admit it took me about 3 weeks to get used to sleeping with the machine. The first night was awful. I have been making minor adjustments to the way I use it for two years, but basically, both my husband and I feel that these machines will add years of health to our lives and keep us from killing ourselves and others while falling asleep at the wheel. I would never have realized I had the disease if I hadn't changed to a newer younger general practitioner who took my blood oxygen saturation level at the beginning of my first visit. It was low and she wouldn't stop until she found out why. It is now normal during the day. It is interesting -- my gripe with my former GP had nothing to do with medicine, just an office policy that I thought was ridiculous. I am so happy that I changed doctors and so is my husband. We are in our mid 60's and are overweight but not diabetic. We are working on losing weight as well, but thank goodness for the C-Pap.